Avast 2017 on WinXP Pro: AvastSVC.exe eating 100% of CPU indefinitely

Avast Free Antivirus / Premium Security
1

System is a fairly normal WinXP SP3 system (Thinkpad x31) with some software installed, but only 65 processes running.
Avast appears to be running normally, but AvastSVC.exe is eating all the CPU cycles, polling something but doing nothing (literally, no change to RAM, IOs, etc), even though the UI is closed and all the filters are disabled.
Have done a complete uninstall/resinstall using the Avast cleanup utility. No change.

Is there some set of parameters I can change to make this less of a CPU hog?

2

Any other security related software running ??? What AV was used before Avast and how was it removed ???

3

Only 65 services running on XP ?
Pff, mine runs with 27 and if I disable the ones not really need only 22.

4

I can top that, mine runs on 20. 8)

5

Was just using Microsoft Security Essentials…did standard uninstall…

6
  • Which Avast…? (Free/Pro/IS/Premier)
  • Which version…?
  • Other security related software installed…?
7

Avast 2017 Free
No other AV software installed (previously had microsoft essentials, removed)
The AvastSvc.exe seems to be fairly well behaved for the first couple of minutes, but as soon as I fire up an application that uses the USB port to communicate to a dongle, CPU utilization by AvastSvc is 100% until the next reboot.

8

What program ???